After Tsar Nicholas II abdicated, the State Duma took over control of the country, establishing the Russian Provisional Government and converting the Empire into a new Russian Republic. When Lenin learned of this from his base in Switzerland, he celebrated with other dissidents. He decided to return to Russia to take charge of the Bolsheviks but found that most passages into the country were blocked due to the ongoing conflict. He organised a plan with other dissidents to negotiate a passage for them through Germany, with whom Russia was then at war. Recognising that these dissidents could cause problems for their Russian enemies, the German government agreed to permit 32 Russian citizens to travel by train through their territory, among them Lenin and his wife. For political reasons, Lenin and the Germans agreed to adhere to a cover story that Lenin had travelled by sealed train carriage through German territory, but in fact the journey was not truly by sealed train because the passengers were allowed to disembark to, for example, spend the night in Frankfurt The group travelled by train from Zürich to Sassnitz, proceeding by ferry to Trelleborg, Sweden, and from there to the Haparanda–Tornio border crossing and then to Helsinki before taking the final train to Petrograd in disguise.

Arriving at Petrograd's Finland Station in April, Lenin gave a speech to Bolshevik supporters condemning the Provisional Government and again calling for a continent-wide European proletarian revolution. Over the following days, he spoke at Bolshevik meetings, lambasting those who wanted reconciliation with the Mensheviks and revealing his "April Theses", an outline of his plans for the Bolsheviks, which he had written on the journey from Switzerland.